The present invention relates to suspensions for vehicles. More particularly, the present invention relates to independent suspensions particularly useful for truck trailers. The inventions described in my other patents, namely U.S. Pat. No. 4,878,691, issued on Nov. 7, 1989; U.S. Pat. No. 4,934,733, issued on Jun. 19, 1990; U.S. Pat. No. 5,016,912, issued on May 21, 1991; and U.S. Pat. No. 5,275,430, issued on Jan. 4, 1994; are all incorporated herein by reference. In addition, my U.S. patent application Ser. No. 09/318,428, filed May 25, 1999 and entitled AXLELESS VEHICLE SUSPENSION SYSTEM is further incorporated herein by reference.
Truck trailers carry a significant volume of cargo over the nation""s roads. Some of that cargo is fragile or vulnerable to vibration and shaking. Unfortunately, some highways and roads are in a deteriorated state and include numerous potholes and cracks. Some highways have pronounced joints and cracks. These deteriorated roads are a threat to movement of fragile cargo.
There are numerous approaches for isolating fragile cargo from roadway disturbances. Some of these approaches include careful packaging of the cargo, use of vibration isolation systems within the trailer, and even modifying the design of the cargo items to make them more rugged. Yet another approach includes modifying the suspension system of the truck trailer to make the trailer less vulnerable to the vibration and pitching movements caused by roadway disturbances. Unfortunately, some of these systems are complex and expensive, and in some cases require specially designed trailers.
What is needed is a suspension system that provides an improved ride while overcoming disadvantages of existing systems. The present invention does this in a novel and unobvious way.
In one aspect of the current invention there is a wheel suspension system for supporting a vehicle from a roadway. The system comprises a vehicle frame with two opposing sides, the frame having a longitudinal axis. A first wheel supports the frame from a roadway from a first side of the frame, the first wheel being rotatably supported about a first rotational axis by a first stub axle pivotally coupled to the frame by a first pivot joint located inboard of the first wheel. There is also a second wheel supporting the frame from the roadway from the other, opposing side of the frame. The second wheel is rotatably supported about a second rotational axis by a second stub axle pivotally coupled to the frame by a second pivot joint located inboard of the second wheel. The first rotational axis is not coincident with the rotational axis of any other sub axle of the vehicle. The second rotational axis is not coincident with the rotational axis of any other stub axle of the vehicle.
These and other aspects of the invention will be apparent from the description, claims, and drawings to follow.